« Posts under Empennage

The Tall Tail

4 hours.

Finally got the tail on.   After some struggles with the rudder bottom and some adjustment of the bearings to make it swing more freely, I got the rudder on, listening to Larry Niven’s “Draco Tavern” on audiobook.   It’s amazing how well audiobooks pass the time.

The rudder wasn’t the only thing I got done; I installed the tailwheel chains and torqued down the tailwheel attach bolts.   Cannot believe I didn’t do those bolts earlier.  I’m lucky I didn’t find the tailwheel rattling around in the truck once we got to the airport.

The rudder bottom may have to have a few things fixed.  I ate away a lot of glass trying to get it to fit properly, so I might have to build it up a bit. I still owe a couple of wraps of UHMW tape around the strobe and light wires.

The only real struggle came from the trim control wire.  I had to get it to pass through a couple of rubber grommets and make its way to the area forward of the VS spar under the empennage fairing.   This was not fun, but my hangar mate Ron helped out by shining a light inside the HS so i could see to jam the wire into the grommet with the two fingers I could stick through the lightening hole.

Somehow I misplaced the cut-off DB9 connector which would have showed me the pinouts for wiring the two ends of the trim wire together.   I remembered writing it down somewhere, but it wasn’t where I thought it was: I devoted an entry on this website to wiring color codes and pinouts but I didn’t remember that at the time.   I called Shelley to see if I’d written it down on some papers I’d stuck to the cork board in the erstwhile shop and she sent me photos of them, but no joy.   I didn’t think to look on this blog, but searching for stuff like that through an iPhone is no fun.

So that’s that.   Just have to get the the trim wired up and a couple of loose ends and the tail is on and attached.   I pushed the plane out into the sun for a photoshoot before I headed home.





Attaching the rudder.

6 hours.

Today was both  productive and frustrating.   The intent was to finish up all things rudder, which didn’t happen, but got pretty close.

I spent a bit of time making some more clearance between the rudder/elevator tips and their corresponding stabilizer tips.   To get a perfectly matched arc shape, I wrapped successive layers of coarse-grit sandpaper around the tip and counterweight, and swinging the part through its travel sanded the stabilizer tip into the shape I needed.   Easy.   But the main focus of the day was the rudder, both wiring and attaching the rudder bottom.

First thing I needed to do was set up the rudder bottom attach, which involved putting  platenuts on the attach strips so I can remove the rudder bottom later if I need to.  This was a time-consuming process, which does not fit well with my “final assembly” ethic.    It needed to be done, along with wiring the tail lamp and strobe.    That went better than expected, but I had to run a ground wire for the tail lamp, which I’d forgotten to do the whole time I was working on stuff back there.



Platenuts.   But not many.


I have no idea why I took this shot.   But this is right about when it started to go south.  When I put the vertical stabilizer on, I put it on with the bolt heads on the inside of the fuselage, with the threads pointing aft.   When I put the rudder on and tried to fit the rudder bottom to it, there was no way in hell the rudder bottom was going to fit.   So I started shaving down the fiberglass on the rudder bottom, which helped.   The major issue was that with the bolts pointed in the wrong direction, the rudder bottom interfered with the center bolt.

Now, this is where you’re saying “turn the bolts around, dude.”   If you had said that when I ran into this problem, it would have helped.  But no, yours truly had to do it the hard way.   I removed the rudder, and figured, hey, I’ll just let the rod end bearings, the ones holding the rudder to the stabilizer, out a bit and see if I can clear those threads.   Nope.   Several tries. Nope.   Without my fancy rod-end-bearing tool, even.   Nope.   After a few rounds of this, I smartened up and flipped the bolts around, and everything clears just fine.   But now my rudder is way out of alignment, and even though it travels nicely and freely, there’s  much bigger gap at the bottom than there is at the top and this will not do.

The good news is that the tail lamp works fine, no smoke, no blown fuses.   The strobe doesn’t, but that’s probably because the strobe pack was last switched on and run some time during the Bush administration and the capacitors are hosed.   I’ll be needing a replacement, and soon, because the wings are going to go on and I’ll need to test that all the blinkenlights work.

So for next time, bring the fancy rod end bearing tool (a couple of scrap pieces of PVC pipe).



Pin the Tail on the Airplane

6 hours.

Last night I loaded the Xterra with all the leftover bits and pieces that didn’t get moved last weekend. All the hardware, the small kit parts, various things in various boxes and the elevator push tube all went up to OXR with me this morning. I spent about an hour unpacking and organizing, and intermittently chatting with folks who stopped by. I met my other hangar mate Scott, and I met Jim, who owns the hangar and seems to know pretty much everything about the airport, and is a vast wealth of knowledge about experimental aircraft in general. Once I’d shuffled things around a bit, I committed to installing the empennage, because it’s another one of those things I don’t want to have on shelves or leaning against something.

20130511-194527.jpgHere, I’ve got the horizontal stabilizer and elevators installed. I had actually forgotten to do a rivet on the HS when I rebuilt the front spar attach bracket, so I did that today. The vertical stabilizer and the rudder also went on, but I have to torque the bolts on the rudder. Also, I need to find the linkage for the tailwheel chain, otherwise steering is going to be interesting. Once I got everything installed, I discovered that the layers of paint on the elevator tips brings it into contact with the tip on the HS. Same with the rudder and VS, so there will be some sanding in the near future. It’s not too bad though, and everything else seems to be pretty good.

20130511-194542.jpgHere’s a shot of all the roommates: The Luscombe, the RV9, and my -7.


20130511-194554.jpgThe last thing I did today was connect the push tube back up to the bellcrank. The stick now operates the elevators, and that is as it should be.

Next time, I need to remember to bring an extension cord and a power strip.

Wiring and fiberglass.

12 hours.

This is for yesterday and today. I finished up the elevator and HS fiberglass tips. You’ve heard me piss and moan about fiberglass before, so I’ll spare you that this time, but yesterday’s experience was not great. I got the HS off the futon in the other room and set it up on the bench so I could mount and balance the elevators. When I last left the HS, I’d done the fiberglass tips, but I hadn’t done much else with them, and they needed a good amount of shaping before the elevators could swing freely. One side was fine after some filing and sandpaper, the other had the foam too close to the edge so I sanded all the way through the filler and started taking out foam.. This isn’t good. Raw foam isn’t helpful, so I had to mix up some flox, both to fill in the elevator tips after balancing and reinforce the left HS tip. I had this cool thing set up where a thin piece of sheet was curved round the elevator tip, making a form for the flox that would guarantee the free motion of the elevator through its travel.

Would have worked too if the tape hadn’t popped loose, leaving me with a distorted lump of flox on the front of one elevator. I had to file/sand that back into shape, then glop in a load of micro filler to get the final shape.

So there it is curing away.

I busied myself with antenna mounts while the epoxy was setting up. First was the transponder antenna. I’ve decided to put this on the floor behind the baggage bulkhead. All antennae need doublers, even the stubby transponder antenna. The skin of the aircraft isn’t thick enough to provide structure on its own, so I had to take a piece of .063 and make a plate that the antenna can grip onto.

Today I did the final shaping and priming of the HS and elevator tips. While I was waiting for paint to dry, I worked on the doubler for the Garmin GPS antenna.

Installing these doublers aft of the baggage bulkhead is interesting. First thing you do is drill the holes in the plate at four corners, then one in che center. Then you go inside the ship, down the Jeffries Tube, and position the plate where you want it for proper antenna location. Don’t forget to bring your drill. Use the plate as a guide, and drill the skin using the center hole in the plate as a guide. Then measure to square the plate up with surrounding stuff, then drill the corners of the plate. Now it gets fun. You have to dimple all four holes in the skin that match the corners of the plate. You need to use your 3/32″ pop-rivet dimpler for this, but you do it by crawling into the ship, placing the dimpler, getting back out, making the dimple, then repeating 3 more times. In the case of the GPS antenna, there are also screw holes to deal with, which means platenuts. Oh, don’t forget to countersink the skin side of the plate.

Since I was in the tailcone a lot today, I figured I’d do some nagging things I was going to have to do anyway, like the restraint cable clevises and removing the ELT antenna cable. Yeah, can’t run the ELT cable through bulkheads. If you crash, the airframe might fold and sever the ELT antenna cable where it passes through a piece of sharp metal. I decided to run the trim servo wire down that run in its place. Then I ran the transponder antenna wire alongside the two GPS wires on the left side and did the BNC connector.

I don’t want to spend a lot more time down there. It’s cramped, hot, and dusty in there. If I can get enough servo wire slack so I can work on the connector outside the ship, that will make me extremely happy.

More emp tips and the strobe head.

4 hours.

You know by now that fiberglass is not my favorite medium in which to create airborne works of art. Mostly it’s the mess, but the big minus is the cure time. I filled the ends of the empennage tips with foam, laid up some fiberglass on each side to stiffen it, then slathered on a nice frosting of micro. I had to take another run at the micro to fill the low spots, but this time I mixed it a little wet. Of course, this necessitates putting the pieces in a position that will allow the filler to flow out flat along the backside, like so:

This tree, cobbled together with clamps, tongue depressors, and scrap angle, allowed the filler to behave as if it was cast in a mold. There’s still a modicum of shaping after this, but these are nearly done.

But I had to do something else while this was curing, so I tackled the thing I know I have the resources for. A while back, I verified that the strobe unit worked. Now it was time to stick it in the plane. I’m going to worry about wire runs later, but I mounted it just behind the baggage comparment bulkhead on the passenger’s side. This is a fairly common location, and will do the job nicely. But I’m out of practice with metal. I went through three plates before I got one that fit right. There are two pieces of angle a little wider than the strobe head, fixed to the J-stringers between the longeron and the floor. Drilling them to the J-stringers was not fun, and neither was riveting them. But they did eventually go in. Here’s a shot of one of the angles clecoed in:

And this with everything assembled and riveted:

Foam arrived, finally.

1.5 hours.

Cut and glassed in the emp tip foam inserts. This damned foam took nearly a month for Aircraft Spruce to get it to my house. It was backordered, then backordered again, and I finally got it today. They sent me a 2×4′ sheet of it too, and I’m pretty sure I ordered a lot less of it. Oh well.

This was easy enough, cut out some foam bits that fill the shape of the fiberglass tips, closing them off to outside elements. Mostly. I applied fiberglass and foam with the tips clecoed on so when the resin dries, I can pull them off and the tips will stay the shape they where when clecoed on. A couple of layups on the inside of the foam block and some micro filler frosting on the outside and those will be done. Then I don’t have to see the empennage again for a while.

Since I had some resin in the pot, I used up all the rest of my cut scraps to glass in the Archer VOR antenna in the wingtip, something I’d been planning to do for a long time but never got around to it. I did two layups on that, which should be enough to hold it in place, it’s not structural, just something to keep the antenna from flopping around in the wingtip. Another thing done.


3 hours.

Aircraft Spruce, for some reason, has twice screwed up getting me my foam that I need to do the empennage tips. OK, fine, plenty of other stuff to do. Like the empennage fairing. This is a fiberglass piece that fits over the place where the tail section is bolted to the fuselage. In theory, you have to pop this on there, drill the holes you need to drill, and fill in whatever gaps are left with flox or some other structural filler. The problem arises when the fit sucks so bad the part looks like it belongs on a different airplane. The only recourse at this point is to start hacking up the fairing and making it fit. Fortunately, fiberglass lends itself very well to this. I had to excise a whole section where the curve of the fairing conflicted with the vertical stabilizer and threw the fit of the whole thing into the toilet. The other thing that had to be done was the part had to be split into two pieces at the front vertical curve. Now it fits. Oh, also, there’s a scribe line around the edges of this part that’s a guide for trimming away the excess. Wish I’d seen that before I started butchering the fairing. With the excess cut away, the fit might have been good enough to just fill the gaps along the edges. I’m tempted to order another fairing and start over. Either that or I’ve bought myself a good 10 extra hours of fumbling around with multiple layups and a crapload of sanding.

But I have to go out of town for five days on business, to rainy, possibly snowy Vancouver BC, so the next chance I get to mess with this thing will be next Monday.


I need five uninterrupted hours to do the glassing. I’m not going to get that.

More emp tips.

3 hours.

Not much today. I did the elevator tips, short of the wet work on the ends. I have to do the counterweight balances before I can rock those out. I’m in the middle of trimming the rudder bottom so it fits right on the flanges, but that’s not getting riveted until the connections are made for the strobe and pos light, and THAT’s not getting done until the light is installed. The rudder bottom will probably have to wait until just before the trip to the airport.

A piece from here, a piece from there…

1 hours.

Last night was one of those “what’s there to do in an hour” nights. Enough time to get something done, not enough time to make a big ol’ mess.

I got some 2″ hose clamps a couple of days ago, so I decided to finalize the cabin vent tubing. OK, as final as anything is on this project. The 2″ black tubing connects the NACA vents on the side to the SteinAir eyeballs at the panel. You twist them one way, air blows out. Twist them the other way, nothing. Just like the ones in airliners. I tested them, they both work and they dont’ seem to leak, but I need to check that. Cold drafts (draughts?) at altitude are bad, because they’re an annoyance that can make a flight suck for a non-rugged-individualist passenger.

After that, I trimmed and drilled the fiberglass tip for the vertical stabilizer. These need to be closed at the back end with some kind of filler, but I didn’t want to make a fiberglass/epoxy mess at 9pm on a weeknight. The crap part is, the filler needs to be put in place while the tip is in place, because there’s no other way to ensure the proper shape due to the tip’s flexing when not pinned down. The VS might have to come off for this, but before it does, I’ll drill the hole necessary for the tail and strobe wires.

Emp Tips.

.5 hours.

I’m trying to get back into the rhythm of doing something, anything, once a day. On my list of odds and ends has been the fiberglass empennage tips, and I’ve been avoiding it because I hate fiberglass and there was always something more important to do. This morning, I did the easiest of the 6 empennage fiberglass parts, the rudder tip:

Easy enough. Cut off the excess with a Dremel, drill, countersink for CS4-4 pop rivets, rivet on. There may or may not be later stages of filler, but at this point, it’s done, it’s on, and it won’t come off. The other tips will need a bit more work, since there’s trimming, and a need to reinforce them. The elevator tips need to be covered up and filled once the counterweights are drilled for balance. But then that’s DONE, and then it’s all about wiring and firewall forward.